1. Field of the Invention
The invention relates to a fluid power linear drive device comprising a housing tube in which a drive piston is accommodated in a linearly slidable manner, said drive piston being kinematically coupled with an output drive slide adapted to run on the outer periphery of the housing tube in the longitudinal direction thereof, there being on the outer periphery of the housing tube, for movably bearing the output drive slide, two guide face pairs each having two guide faces extending along the housing tube and being arranged opposite each other in the axial direction of a first transverse axis of the housing tube, said two guide face pairs being spaced apart in the axial direction of a second transverse axis which is perpendicular to the first transverse axis.
2. Brief Description of the Related Art
In the case of a linear drive device of this type as disclosed in the European patent publication EP 0 603 471 B1 the drive piston is drivingly connected in a contact-free fashion by means of a permanent magnet coupling means with the output drive slide. The housing tube has an elongated cross section, the magnetic forces produced by the coupling means being mostly effective at a right angle to the longitudinal axis of the housing tube's cross section. The transitional regions between the narrow sides and the wide sides of the housing tube are designed in the form of guide faces, on which the output drive part slides.
In the case of an uneven distribution of the magnetic coupling forces the contact portion between the output drive part and the housing tube may entail undesired wear. In order to avoid this to a maximum extent highly accurate manufacture and fitting of the individual components is required with close tolerances. This results in there being relatively high costs of manufacture.
The German patent publication DE 34 36 977 C2 discloses a linear drive whose housing tube is provided with axially extending slanting guide rails on its output periphery for a slide to run on using suitable rolling parts.
The German patent publication DE 101 43 878 B4 discloses a linear setting member with a slide rider, which is coupled by magnetic forces with a piston able to be driven by a fluid.